Manufacture of molded articles from cement



ice. COMPOSITIONS: comma R PLASTIC.

UNITED STATES PATENT OFFICE.

WALTER EDWIN WINDSOR RICHARDS, 0F SOUTHALL, ENGLAND.

MANUFACTURE OF MOLDED ARTICLES FROM CEMENT.

\, 1,408,401. I Specification of Letters Patent. Patented Feb, 28, 1922,

No Drawing. Application filed November 29, 1918. Serial No. 264,622. I 1

T0 allwkom it may concem: as an admixture to ground Portland or like I Be it known that I, WALTER EDWIN WIND- cement for the purpose of cinematic cemen f. son RICHARDS, a subject of the King of Great either with or withopt tl e pddi t ipn of as- Britain and Ireland, residing at The Green, bestos fil ge to ow more easnfinm tlie ln- 60 Southall, Middlesex,'England, have invented terst-lces in. the molds.

certain new and useful Improvements in and It has previously been proposed to mix Y Relating to the Manufacture of Molded Arpuzzuolana or. cla with Q11.;1d ement ticles from Cement, of which the following clinker and su sequently rindthe mixture I is a specification. to cement, the object being to gramme-a 65 i This invention relates to improvements in cement particularly suitable for ferro-conthe manufacture of molded articles from crete work or for structures which have to 1 cement. The invention is particularly dewithstand the action of sea water. The pressigned to enable articles of an irregular ent invention differs from this process in shape or of such shapes into the molds for that it relates to a cement to be used for 70 which ordinary cement can only with difmaking articles by a pressure molding operaficulty be caused to flow, to be satisfactorily tion, and has no relation to any uses conconstructed, and it relates more particularly nected with ferro-ooncrete or building operastill, but not exclusively, to the manufacture tion; furthermore the clay, which is used of articles intended to be treated by a process only for the purpose of increasing the flow-u 75 of impregnation for the purpose of rendermg properties of the cement is added to ing them suitable for use as electric insulaordinary already ground cement.

tors, although the process The invention is carried out as follows 'e ctof'the present invention, will be found In giving a detailed description of the to be applicable to other purposes besides method of carrying out the process, it should 80 the one referred to. be understood that this is given by way In the manufacture of the class of arof an example of the preferred process, and ticles referred to, it is usual to make a one which will yield satisfactory results for mo ded a er of cement alone r ordinary articles, but it is not desired to of cfilw ilith the a ition o s estos or limit the invention to the precise details of 85 like fibre nd imme quantities or other minor routine details fitfflia fiifipregnating material, and the finthat are given. The cement used should ished article, particularly if it is to be preferably be ordinary Portland cement, used for the purpose of electric insulation, preferably not too quick setting. A mixture should be capable of taking a fine polish, is made containing 30 arti g f Portland 90 being screw threaded and otherwise worked cement 15 arts of waste asbestos re an to fit the particular circumstances under Ill arts of cla e "c ay "may be which it is to be used. Difficulties have China cla Ball clay or even ordinary clay been experienced in molding some of these or fire-clay and it should preferably be dried articles, particularly in cases where the mold and powdered, These ingredients are thor- 95 is of irregular shape, or, for instance, where oughly mixed in any suitable mixing mait contains flanges or other interstices, the chine and the mixture 'is stored in a bin reason being that the mixture, particularly orother suitable receptacle, from which it 4 if the cement has been mixed with asbestos can conveniently be drawn.

' fibre, is very diflicult to cause to flow, and 25 to 30 lbs.-of this mixture are found to 100 it is found that it frequently does not combe a convenient quantity for a charge for pletely fill the mold, the pressure being taken making the molding composition, and this locally. amount of mixture is thoroughly mixed in Now the object of the present invention a suitable machine with three quarts of w is to overcome this difiiculty and to provide ter. This wet mixture is then used for t e 105 means for making the mixture flow more purpose of molding the desired articles by easily, so that molded articles of irregular any known or convenient method. shape or which contain interstices or the The molding should preferably be carlike can more easily be manufactured than ried out before the initial set of the cement heretofore, without such means damaging the has taken place, as it will be found that bet- 110 properties of the finished article. ter results are obtained in this way, it be- The invention consists in the use of clay ing well known that cement, although it Qu cywt 3 0 e [LAM l y 4 I (alg will set in time, requires a long time to do so if it is disturbed after the initial set has taken place, and the resulting articles are likely to be less satisfactory in the latter case. This fact is the reason why it is desirable, if possible, not to use quick setting h ii h f 1d g. d d

atever met od 0 mo in is a opte the process should be accompanied by a certain amount of pressure, the pmsm-heglg su ment to remove any excess of water and leave an alit cg g s ien stren h or it (tiqbe capableof withstanding care flil han- The molded articles are then stored, preferably in racks open to the air for varying periods according to their thickness. They are then placed into a cold or W van and gradually heated to a temperature of abou ees Fahr. for a period of about 24 hours. If the articles are intended to be impregnated, they are then put into the impregnatmf vessels and treated in the ordinary way. t should be noted that if it is desired to use the process which is the subject of this invention for making extruded tubes, the mixture will require to be varied, less asbestos or none at all being used in this case. The proportions for making tubes may be equal amounts of clay and cement. Suitable methods of and materials for impregnating the articles made are described in the specification of British Letters PatentNo. 3364 of 1915, corresponding Letters Patent of the U. S. and No. 1,267,- 696 of May 28, 1918, granted to me.

As has been stated, the above details are given by way of example and constitute the ordinary working process suitable for most articles, but the mvention is not limited to such details. For example, mixtures of different clays may be used and the proportions of the ingredients may also be varied within reasonable limits.

cases glass wggl may with advantage be used instea o as estos.

Mixtures made in accordance with this invention will be found to flow under pressure far more easily than has hitherto been found to be the case.

It may be found that the crushing or tensile strengths to which molded articles made in accordance with this invention can be subjected without breaking, will be less than those to which articles made without the addition of clay can be subjected, and it should be noted that the invention is primaril but not exclusively, intended to be used for the manufacture of such articles as are not required to withstand very high stresses.

It should further be noted that the addition of clay to the mixture causes the article to be capable of taking an even finer polish than is the case where clay is not used, the articles at the same time bein quite suitable for being worked or fitte with screw threads.

I claim:

1. The method of making molded cement articles which consists in adding powdered clay up to ten parts to; a mixture of from thirty to forty-five parts of ground cement and fiber, and mixing the same therewith, then mixingthe resultant composition with water to form a freely flowing mixture, molding the desired article under pressure.

2. A com osition of matter consisting of WALTER EDWIN WINDSOR RICHARDS.

Witnesses:

FRANK B. DEHN, G. P. Yomw. 

